ISSN 1028334X, Doklady Earth Sciences, 2011, Vol. 437, Part 1, pp. 437–441. © Pleiades Publishing, Ltd., 2011. Original Russian Text © G.G. Matishov, A.Sh. Gasanova,G.V. Kovaleva, 2011, published in Doklady Akademii Nauk, 2011, Vol. 437, No. 3, pp. 404–408. OCEANOLOGY Effects of Changes in the Hydrological and Hydrochemical Regime of the Caspian Sea on the Development of Microalgae in the Coastal Zone Academician G. G. Matishova, b, A. Sh. Gasanovac, and G. V. Kovalevaa Received July 28, 2010 Abstract—This paper analyzes the composition and distribution of coastal phytoplankton in the western por tion of the Middle Caspian in the context of changes in the hydrological and hydrochemical regime under the conditions of the rising level of the Caspian Sea. It has been demonstrated that the changes in the water regime led to an increase in the taxonomic diversity, the quantitative characteristics of phytoplankton, and the succession of the size groups. DOI: 10.1134/S1028334X11030263 The Caspian Sea is a unique natural drainless tory. This was most manifest in the TerekSulak area brackish water body. The long term and annual fluctu (the northwestern portion of the Middle Caspian), ations in the level typical of the Caspian Sea are regu where marine conditions have existed on the flooded lar processes reflecting the cyclic changes in the ambi territory for over 30 years [8]. ent environment [14, 15]. Due to this, the Caspian Sea A large number of studies have been dedicated to can be a natural model for examination of the internal examination of phytoplankton in the Middle Caspian characteristics and environmental consequences of [2, 3, 7–10, 12, etc.]. However, all of them refer to the the global processes associated with the fluctuations in period when the level of the Caspian Sea was low. the level of the World Ocean. There are no data published in the last 25–30 years on Phytoplankton has a substantial significance in the the status of coastal algocenoses of the shallow por biological productivity of the seas and is a sensitive tions within the western coast of the Middle Caspian. indicator of all changes occurring in the ecosystem. Given that such investigations would be of immediate The nature and degree of the development of phy interest, the authors examined the presentday status toplankton govern the progress of production pro of phytoplankton in the coastal shallows within the cesses in the ecosystem as a whole. The short life span western portion of the Middle Caspian, which is an of microalgae and their ability to adequately react to extremely important fishing ground. changes in the quality of the habitat allow making an integral assessment of all natural and anthropogenic MATERIAL AND METHODS processes occurring in the water body. This study presents data on examination of coastal As is well known, the current transgression of the shallows in the western portion of the Middle Caspian Caspian Sea, biological invasions, and anthropogenic collected during the joint cruise organized by the contamination, along with natural climate variations, Southern Scientific Center of the Russian Academy of led to a transformation of the autochthonous biota of Sciences and the Caspian Institute of Biological the water body. These processes are particularly Resources of the Dagestan Science Center of the Rus noticeable in the coastal shallow water zone. The rise sian Academy of Sciences during the period August of the level of the Caspian Sea that started in 1979 21–29, 2006, in the Kizlyar and Sulak gulfs and of the caused a flooding of the Caspian coast on a large terri coastal water zones near the towns of Makhachkala, Izberbash, and Derbent using small vessels (Fig. 1). Phytoplankton was collected using a Molchanov a Southern Scientific Center, Russian Academy of Sciences, barometer and fixed with acid Lugol’s solution. The pr. Chekhova 41, RostovonDon, 344006 Russia fixed samples were settled under darkroom conditions b Murmansk Marine Biological Institute, Kola Science for at least 15 days and were concentrated using the Center, Russian Academy of Sciences, ul. Vladimirskaya 17, settling method [13, 1]. The number of cells was cal Murmansk, 183010 Russia culated in a Nageotte chamber (volume 0.1 mL) with c Caspian Institute of Biological Resources, Dagestan Science three replications under a Micmed6 light microscope Center, Russian Academy of Sciences, ul. Gadzhieva 45, (magnification ×400 and ×200). The biomass of the Makhachkala, 367000 Russia algae was calculated using the formulas of geometric 437 438 MATISHOV et al. Kizlyar Gulf Suyutkino CASPIAN Bol'shaya Areshevka SEA Tarumovka KOMSOMOL’SKII Krainovka Aleksandriiskaya Staroterechnoe KIZLYAR Babayurt Khamamatyurt TamazaTyube Tatayurt Novaya Kos Shelkovskaya Sulak Gulf GUDERMES KHASAVYURT KIZILYURT Novolakskoe Dylym NozhaiYurt MAKHACHKALA Sulak Gulf BUINAKAS Sulak Karabudakhkent Untsukul IZBERBASH DERBENT Gergebil Fig. 1. Map showing phytoplankton sampling locations. similarity of cells. The abundance of cells was salinity of the water on the beam of the Terek River is expressed as mln cells/m3, and the abundance of all 6‰, in the Makhachkala area, 10‰, in the water phytoplankton and individual species was estimated zone of the town of Izberbash, 11.2‰, and in the from the wet weight in mg/m3 and g/m3. southern portion of the coast, 12.85‰. The amplitude of synoptic and seasonal fluctuations in the salinity of the coastal waters is quite large. Despite the desalinat RESULTS AND DUSCUSSION ing effect of the flow of the rivers of Dagestan and the The coastline of the water zone of the Middle Cas water from the northern portion of the Caspian Sea, pian, which is 530 km long, is characterized by a wide the salinity gradient between the extreme values is range of space–time variability of water salinity. The over 7‰. This is the reason for the uneven distribution hydrological regime of the examined water zone was of algal flora in different parts of the water zone of the formed under the influence of the flows of the Volga, Middle Caspian [4, 5]. Terek, and Sulak rivers. While the average salinity of The formation of the phytoplankton community the Middle Caspian water is 12.84‰, the average during the period of the investigations occurred under DOKLADY EARTH SCIENCES Vol. 437 Part 1 2011 EFFECTS OF CHANGES IN THE HYDROLOGICAL AND HYDROCHEMICAL REGIME 439 Spatial distribution of the principal taxons of microalgae of summer phytoplankton in the coastal shallow water zone within the western portion of the Middle Caspian in 2006 Kizlyar Gulf Sulak Gulf Makhachkala Izberbash Derbent Total Area N % N % N % N % N % N % Bluegreen Cyanophyta 12 35.3 5 20.0 7 24.1 2 18.2 2 13.3 12 20.7 Diatoms Bacillariaphyta 10 29.4 8 32.0 8 27.6 6 54.5 7 46.6 22 38.0 Dynophytaе Dinophyta 3 8.8 8 32.0 12 41.4 3 27.3 4 26.7 13 22.4 Euglena Euglenophyta 1 3.0 1 1.7 Green Chlorophyta 8 23.5 4 16.0 2 6.9 1 6.7 9 15.5 Other (small flagellate) 1 6.7 1 1.7 Total 34 100 25 100 29 100 11 100 15 100 58 100 sea transgression conditions. Desalinization of the desalinating influence of waters from the northern water zone promoted an expansion of the species portion of the Caspian Sea. The Kuma, Prorva, Levyi diversity and quite high values of the abundance and Banok, and Talovka rivers fall into it. The gulf is shal biomass of phytoplankton. During the investigations low and is characterized by high hydrodynamic activ 58 species and varieties of microalgae belonging to five ity of the water mass and a large quantity of invading divisions were discovered. For comparison, the num desalinized water [6]. The water salinity varies from 5 ber of species encountered in the water zone of the to 7‰. Passive flooding of the coast caused by marine entire Caspian Sea was 62 in 1976 and 37 in 1983 [11]. transgression is observed there. The maximum floristic diversity was observed for dia During the period of our investigations, high taxo tom algae (22 species), which is 38% of the total spe nomic diversity (see table) and the maximum values of cies diversity. The contribution of dynophyta and the biomass and abundance of plankton microalgae bluegreen algae is 22.4 and 20.7%, respectively. The (Fig. 2) were observed in the Kizlyar Gulf. taxonomic structure of the phytoplankton is shown in the table. The number of species in the samples from the Kiz lyar Gulf varied from 11 to 25. Fresh water and brack The values of the biomass and abundance of ish water species primarily developed in phytoplank microalgae in the examined water zone of the Middle 2 3 ton. Bluegreen algae were characterized by the maxi Caspian were 2948.0 mg/m and 568.5 mln cells/m , mum diversity in terms of the species composition respectively (Fig. 2). An increase in the proportion of (12 species); they accounted for 75% of the total bluegreen algae was observed (up to 68.8%), which abundance. The most frequently observed varieties were leaders in the abundance. The main contribution were Oscillatoria sp., Aphanothece clathrata W. et G.S. to the formation of the biomass was made by diatoms West, Gomphosphaeria lacustris Chod., Anabaena flos (74.1%). aquae (Lingb.) Breb., A. bergii var. minor Kissel., Mer An important feature of the development of phy ismopedia punctata Meyen, etc. Although Aphanothece toplankton in the coastal zone should be noted: clathrata prevailed in terms of the abundance, the against massive development of smallcelled species, the leader of the previous years (the largecelled dia tom Pseudosolenia calcaravis) [2, 3] was not found.